A nice solution is that every developer adds lines or blocks to random places in a list or a file, but a better solution is to sort these lines (especially for lists like composer.json, translation files, etc…). This way you insert new lines in “random” places, keeping it clear for everyone how things are added.

Something that does not work for composer.json, but something I highly recommend, is to add trailing commas in PHP arrays and to not align code (see the blogpost by Made With Love about “How clean are your diffs?”). This eases up merging too!

Now you can create a “parent” class to register the databases (mine is called DatabaseTest). Make sure you create a getDatabaseConfigs method (which is required and should return an array of PHPUnit_Extensions_MultipleDatabase_Database). For the fixtures, I use Xml Datasets, which look like this.

I’ve added a getConnection method, so I can use the same assertions as the normal dbunit testcase (see Database Assertions API):

The magic about to happen is quite cool. PHPUnit will read these database configs and use them to make sure all databases and tables are in a known state before every test and does this in following order:

Connect to all databases

TRUNCATE all tables supplied in the database fixture file

Insert all rows supplied in the fixture file

Execute the test

TRUNCATE all tables supplied in the database fixture file

Now you’ll be able to run tests for code making changes in your database without affecting other tests.